AMINOGLYCOSIDES, PROCEDE DE FABRICATION ET APPLICATIONS

AMINOGLYCOSIDES, PROCESS FOR PRODUCTION THEREOF, AND USE THEREOF

Abrégé anglais

ABSTRACT OF THE DISCLOSURE
Novel aminoglycosides of the following formula
<IMG>
wherein R1 and R2 are identical or different and each
represents a hydrogen atom or a methyl group, R3 represents
a hydrogen atom or an optionally substituted aminoacyl
group having 2 to 4 carbon atoms in the acyl moiety, and
when all of R1, R2 and R3 are hydrogen atoms, the methyl-
amino group at the 4-position is not oriented trans to
the hydroxyl groups at the 3- and 5-positions; and acid
addition salts thereof, which are useful as antibiotics;
and process for producing compounds containing the same.

Revendications

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for producing a compound of the formula
<IMG> (I)
wherein R1 and R2 are identical or different and each represents a hydrogen
atom or a methyl group and R3 represents a hydrogen atom or an optionally sub-
stituted aminoacyl group having 2 to 4 carbon atoms in the acyl moiety, the
substituent being selected from formyl or carbamoyl group, provided that when
all of R1, R2 and R3 are hydrogen atoms, the methylamino group at the 4-
position is not oriented trans to the hydroxyl groups at the 3- and 5-positions
or a pharmaceutically acceptable acid addition salt thereof which process com-
prises reacting a compound of the formula (II)
<IMG> II
wherein R1 and R2 are as defined above and R3 represents a moiety selected from
the group consisting of a hydrogen atom, -COCH2NH2, -COCH2NHCONH2 and

-COCH2NHCHO, with a strong acid and, if required, protecting a compound of
formula I wherein R3 is a hydrogen atom in its amino groups at the 1- and 2'-
positions and the amino or methylamino group at the 6'-position, then acylating
it with an optionally substituted amino acid having 2 to 4 carbon atoms in the
acyl moiety and a protected amino group or a reactive derivative thereof, the
substituent being selected from formyl or carbamoyl group, and then splitting
off the protective groups, and, if required, converting the product to a pharm-
aceutically acceptable acid addition salt thereof.
2. A compound of formula I as defined in claim 1 or a pharmaceutically
acceptable acid addition salt when prepared by a process according to claim 1
or an obvious chemical equivalent thereof.
3. A process according to claim 1 wherein R1 is a methyl group, R2 is a
hydrogen atom and R3 is a glycyl group.
4. A process for preparing the compound de-O-methyl-KA-6606 I
<IMG>
or its pharmaceutically acceptable acid addition salt, which comprises heating
the compound KA-6606 II of formula
36

<IMG>
with hydrobromic acid, or reacting the compound KA-6606 II with boron tri-
chloride with cooling, to convert the methoxy group in the 5-position to a
hydroxy group and thereby obtain de-O-methyl-KA-6606 II, reacting this compound
with N-benzyloxycarbonyloxy succinimide to protect the three primary amino
groups of de-O-methyl-KA-6606 II, reacting the protected compound with N-
hydroxysuccinimidyl-N-benzyloxycarbonylglycine to obtain tetrakis-N-benzyloxy-
carbonyl-de-O-methyl-KA-6606 I, subjecting this compound to hydrogenolysis to
remove the benzyloxycarbonyl groups and, if a pharmaceutically acceptable acid
addition salt is required, reacting the product with a pharmaceutically accept-
able acid.
5. The compound de-O-methyl-KA-6606 I as defined in claim 4 or a
pharmaceutically acceptable acid addition salt thereof when prepared by a pro-
cess according to claim 4 or an obvious chemical equivalent thereof.
6. A process according to claim 4 wherein the obtained de-O-methyl-KA-
6606 I is converted into the hydrochloride salt by reaction with hydrogen
chloride.
7. The hydrochloride salt of de-O-methyl-KA-6606 I when prepared by a
process according to claim 6 or an obvious chemical equivalent thereof.
8. A process for preparing the compound de-O-methyl-4-N-glycyl-KA-6606 VI
37

<IMG>
or its pharmaceutically acceptable acid addition salt, which comprises heating
the compound KA-6606 VI of formula
<IMG>
with hydrobromic acid or hydriodic acid, to convert the methoxy group in the 5-
position to a hydroxy group and thereby obtain de-O-methyl-KA-6606 VI, reacting
this compound with N-benzyloxycarbonyloxy succinimide or benzyl p-nitrophenyl
carbonate, to protect the three primary amino groups of de-O-methyl-KA-6606 VI,
reacting the protected compound with the 2,4-dinitrophenyl ester of N-benzyloxy-
carbonylglycine or with N-hydroxy-succinimidyl-N-benzyloxycarbonylglycine to
obtain 1,2',6'-tris-N-benzyloxycarbonyl-4-N-benzyloxycarbonylglycyl-de-O-methyl-
KA-6606 VI, subjecting this compound to hydrogenolysis to remove the benzyloxy-
carbonyl groups and, if a pharmaceutically acceptable acid addition salt is
required, reacting the product with a pharmaceutically acceptable acid.
9. The compound de-O-methyl-4-N-glycyl-KA-6606 VI as defined in claim 8
or a pharmaceutically acceptable acid addition salt thereof when prepared by a
process according to claim 8 or an obvious chemical equivalent thereof.
38

10. A process according to claim 1 wherein R1 is a hydrogen atom, R2 is a
methyl group and R3 is a glycyl group.
11. A process for preparing the compound de-O-methyl-KA-7038 I
<IMG>
or its pharmaceutically acceptable acid addition salt, which comprises heating
the compound KA-7038 III of formula
<IMG>
with hydriodic acid to convert the methoxy group in the 5-position to a hydroxy
group and thereby obtain de-O-methyl-KA-7038 III, reacting this compound with
N-benzyloxycarbonyloxy succinimide to protect the amino groups at 1,2',6'-
position of de-O-methyl-KA-7038 III, reacting the protected compound with the
2,4-dinitrophenyl ester of N-benzyloxycarbonylglycine or with N-hydroxy-
succinimidyl-N-benzyloxycarbonylglycine to obtain tetrakis-N-benzyloxycarbonyl-
de-O-methyl-KA-7038 I, subjecting this compound to hydrogenolysis to remove the
benzyloxycarbonyl groups and, if a pharmaceutically acceptable acid addition
salt is required, reacting the product with a pharmaceutically acceptable acid.
39

12. The compound de-O-methyl-KA-7038 I as defined in claim 11 or a pharm-
aceutically acceptable acid addition salt thereof when prepared by a process
according to claim 11 or an obvious chemical equivalent thereof.

Description

~5~2~35
This invention relates to novel aminoglycosides useful as antibiotics,
a process for production thereof, and the use thereof.
More specifically, this invention relates to compounds of the follow-
ing formula
IRl
61 CH-NH-R2 NH2
~ o ~ ~OH
NH2 7- CH3
R3
wherein Rl and R2 are identical or different and each represents a hydrogen atom
or a methyl group, R3 represents a hydrogen atom or an optionally substituted
aminoacyl group having 2 to 4 carbon atoms in the acyl moiety, the substituent
being a formyl or carbamoyl group, provided that, when all of Rl, R2 and R3 are
hydrogen atoms, the methylamino group at the 4-position is not oriented trans
to the hydroxyl groups at the 3- and 5-positionsi and the pharmaceutically
acceptable acid addition salts thereof.
The present inventors have now found that the novel compounds of
formula I having a hydroxyl group at the 5-position exhibit higher antibiotic
activity than compounds of formula II having -OCH3 at the 5-position, and that
the compounds of formula I can be advantageously produced in high yields by
less process steps by treating the compounds of formula II having a methoxy
group at the 5-position with strong acids, optionally followed by acylation.
It is an object of this invention to provide novel compounds useful
as antibiotics and a process for production thereof.
The compound of formula I can be prepared by a process which comprises
reacting a compound of the formula II ~

~5~;~8S
Rl
6 CH-NH-R2 NH
~ -OCH3 Ir
NH 2 R 3CH3
wherein Rl and R2 are as defined above and R3 represents a moiety selected from
the group consisting of a hydrogen atom, -COCH2NH2, -COCH2NHCONH2 and
-COCH2NHCHO, with a strong acid and, if required, protecting a compound of
formula I wherein R3 is a hydrogen atom in its amino groups at the 1- and 2'-
positions and the amino or methylamino group at the 6'-position, then acylating
it with an optionally substituted amino acid having 2 to 4 carbon atoms in the
acyl moiety and a protected amino group or a reactive derivative thereof, the
substituent being selected from formyl or carbamoyl group, and then splitting off
the protective groups, and, if required, converting the product to a pharmaceuti-
cally acceptable acid addition salt thereof.
Some of the compounds of formula II are known. Specifically, among
the starting compounds of formula II, those of the following formula
fH3
6~ CH-NH 2 NH 2
3 A
NH2 1_CH3
R3
~ - 2 -
L~,

.5~2~35
wherein R3 represents a moiety selected from the group consisting of hydrogen,
-COCH2NH2, -COCH2NHCONH2 and -COCH2NHCHO; and the acid addition salts thereof
are known as antibiotic KA-6606 or sporaricin (for example, West German
Offenlegungsschrift No. 2,813,021 published on October 5, 1978).
As described in detail in the German specification, the compounds of
formula A can be produced by a process which comprises cultivating an antibiotic
KA-6606-producing strain of the genus Saccharopolyspora and isolating the anti-
biotic KA-6606 from the culture broth. A typical strain is Saccharopolyspora
hirsuta KC-6606 strain. This strain was deposited as FERM-P No. 3912 in
Fermentation Research Institute, Agency of Industrial Science & Technology,
Japan; as ATCC Number 20501 in American Type Culture Collection; and as DSM
1238 in German Collection of Microorganisms (Deutsche Sammlung von Micro-
organismen).
As disclosed in the German Offenlegungsschrift No. 2,813,021, the
known antibiotic KA-6606 can be further separated into four antibiotics
KA-6606 I, KA-6606 II, KA-6606 III and KA-6606 IV, and the KA-6606 I, KA-6606
III and KA-6606 IV can be readily converted to KA-6606 II by treatment with
alkalies or acids. Other antibiotics KA-6606 V and KA-6606 VI can be separated
from antibiotic KA-6606. The molecular formulae and specific rotations of
KA-6606 I to VI which belong to the starting compounds of formula A are given
below.
Molecular
Antibiotics formula Specific rotation
KA-6606I 17 35 5 5 [~] + 104 (c 1, H2O)
KA-6606II 15 32 4 4 [~]D + 139.5 (c 1, H20)
KA-6606III 18 36 6 6 [~] + 103 (c 1, H2O)
KA-6606IV 18 35 6 5 [~] + 101 (c 1, H2O)
KA-6606V 15 32 4 4 [~]25 + 103 (c 1, H2O)
KA-6606VI 15 32 4 4 [~]25 + 54 (c 1, H2O)
- 3 -

Z~5
The groups Rl, R2 and R3 of KA-6606 I to VI in formula II are tabu-
lated below.
Rl R2 R3
KA-6606I CH3 H COCH2NH2
KA-6606II CH3 H H
KA-6606III CH3 H COCH2NHCONH2
KA-6606IV CH3 H COCH2NHCHO
KA-6606V CH3 H H
KA-6606VI CH3 H H
KA-6606II, V and VI differ in steric configurations at the 1- and 4-
positions, as follows:
~ ~ KA-6606 II
NH2
~ OCH3 KA-6606 V
CH3
NH2
~ o ~ H KA-6606 VI
OCH3
' ~,
: -

28S
The specification of the German Offenlegungsschrift 2,813,021 disclosesin detail the separation of KA-6606 I to IV corresponding to formula A. KA-6606
V and VI can be separated similarly during the separation of KA-6606 I to IV
from crude KA-6606 obtained in the manner disclosed in the above German specifi-
cation. For example, the crude KA-6606 i.s caused to be adsorbed to an adsorbent
such as a weak acid-type cation exchange resin, CM-Sephadex* or CM-cellulose,
and eluted by a gradient method or a stepwise method using aqueous ammonia, an
aqueous solution of ammonium carbonate, an aqueous solution of ammonium formate,
etc. First, several trace components are eluted, and KA-6606 IV and then
10KA-6606 III are eluted as free bases. On further elution, KA-6606 I, VI and II
substances are sequentially separated, and finally K~-6606 V is separated.
These components obtained can be purified by properly combining
chromatography on cellulose, silica
*Trade Mark
, 5

~5~Z85
gel, etc., and chromatography on Sephadex* series such as LH20. For example,
they can be purified by chromatographing with chloroform/methancl/17% ammonia
solution (1:8:3) on a silica gel column.
The free bases obtained are then charged on a column of a strong base-
type anion exchange resin such as Dowex* lX2 (a product of Dow Chemical Company)
and eluted with water, for example. The active fractions were collected and
lyophilized to obtain pure free bases. These free bases can be converted to -
the corresponding acid addition salts in a customary manner by adding inorganic
acids such as hydrochloric acid, sulfuric acid, hydrobromic acid or carbonic
acid, or organic acids such as acetic acid or oxalic acid.
~1
Other compoundsof formula (II) 1 used as a starting material in this
invention are called antibiotics KA-7038 or sannamycin. The antibiotics
KA-7038 can be produced by a process which comprises cultivating an antibiotic
substance KA-7038-producing strain belonging to the genus Streptomyces, and
isolating the antibiotic substance KA-7038 from the culture broth. A typical
strain is Streptomyces sp. KC-7038. This strain KC-7038 was deposited as
FERM-P No. 4388 in Fermentation Research Institute, Agency of Industrial
Science &
*Trade Mark
~ _
, ' ~ ' '~ '~ . '
: ,

~5~3'~35
Technology, Japan; as ATCC number 31530 in American Type Culture Collectioni and
as DSM No. 1594 in German Collection of Microorganisms.
The substance YA-7038 can be further separated into seven antibiotics,
YA-7038I, YA-7038II, YA-7038III, Y~A-7038IV, YA-7038V, YA-7038VI and YA-7038VII,
and they can be readily converted to acid addition sal-ts thereof by treatment
with acids.
The formulae and physical and chemical properties of the starting
Y~A-7038 I, III and V to VII are given below.
Substance YA-7038I:
CH 2NHCH3 NH 2
~ ~ 3
NH2 OCH3
Molecular formula: C17H35O5N5
Specific rotation: [~]D + 120.5
(C 1, H20)
Melting point: 83 - 90 C
Substance Y~A-7038III:
CH 2NHCH3 NH 2
CH 3
NH 2 OCH 3
- 7 -

~.i5~;285
Molecular formula: C15H32O4N4
Specific rotation: [~]D + 78 (c 0.5, H2O)
Meltin~ point: 74 - 83 C
Substance ~A-7038V:
~H2NH2 NIH2
r~
OCH3
NH2 NHCH3
;
,

~1150Z85
Molecular formula: C14H3004N4
E Specific.rotation: ~D5 + 98 (c 0.. 5, H20)
Substance KA-7038VI:_
CH21~iICX3 I`IH2
)\ /\OL~I
NH2
Molecular formula: C15H3204N4
Specific rotation: ~a~25 + 58 (c 1, H20)
Substance I~A-7038VII:-
CH2~iI2 N~2
OCH3
l~H2 I~HCH3
Molecular formula: C14H30041~4
Specific rotation: ~a)D5 + 59 (c 1, H20)
In the present invention, the antibiotics
KA-7038 can be obtained by cultivating a EA-7038-produc-
3/s30
ing strain such as ~RM-P l~o. 4388 strain or ATCC ,1,,~
strain in a nutrient medium containing a carbon source,
a nitrogen source and minerals, and separating KA-7038
from the culture brothO
Suitable culture media for use in fermenting
the substance EA-7038-producing strain of the genus
streptomyces comprise carbon and nitrogen sources and
as optional ingredients, inorganic salts (minerals),
,. ~
:

285
i~
very small amounts of heavy metals, etc.
Vario-us carbon sources ca7l be used, and
examples of preferred carbon sources are glucose, starch,
sucrose, fructose, dextrin, molasses and glycerol, which
can be used either alone or as suitable mixtures. Hydro-
carbons, alcohols, organic acids and vegetable oils can
also be used if the strain used can utilize them as a
carbon source.
Examples of nitrogen sources are soybean meal,
yeast extract, dried yeast, pep-tone, meat extract, corn
steep liquor, Casamino acid, Distiller's soluble,
ammonium chloride, ammonium sulfate, ammonium nitrate,
urea and sodiwn nitrate, which can be used either alone
or as suitable mixturesO Examples of inorganic salts
include sodium chloride, nitrates, calcium carbonate,
potassium chloride, cobaltous chloride and ferrous
sulfate.
Inorganic substances and organic substances
(e-gO~ amino acids) which aid in the growth of the
strain and promote the production of substance KA-7038
can also be added to the culture medium as requiredO
~hen an aerating cultivation method is employed, an
antifoamer such as fatty acid oils, silicone oils,
cotton seed oil and paraffins can also be added to the
culture mediumO
Cultivation may be carried out in a solid
medium~ Preferably, however, same as in the general
process for producing antibiotics, a liquid cul-tivating
,~ ~

~15f3285
methocl, especially a submerged cultivation method, is
~` used~ The cultivation is carried out under aerobic con-
~. . i~
ditions, and the cultivation temperature is preferably
about 20 to about 35C~ more preferably about 24 to
about 27Co Preferably, during the cul-tivation, the p~
of the culture medium is maintained at about L~ to about
10. The cul-tivation period is generally about 2 days to
about 10 days.
As a result of the cultivation, the substance
10 KA-7038 is produced and accumulated in the culture broth.
When the amount of the substance KA-7038 produced in the
culture broth reaches a maximum, the cultivation is
stopped. 'rhe substance KA-7038 can be collected from
the culture broth.
~ince the substance E~A-7038 is a water-soluble
A basic substance oolublc ~n ~er but difficultly soluble
in common organic solvents, it can be separated from
the culture broth by utilizing the procedures which are
customarily used in isolating and purifying water-
soluble basic antibiotics. For example, there can be
used an adsorption desorption method using an ion e~-
change resin, active carbon etc.; column chromatographic
method using cellulose, silica gel, alumina, etc.; and
a method for extracting with butanol, amyl alcohol, etc.
using a higher fatty acid as an adjuvant~
~ or example, if the culture broth filtrate is
charged on a column of a weak acidic ca-tion exchange
resin, the substance ~A-7038 is adsorbed to it. ~he

~328S
substance KA-7038 is -then isolated by elution with a
,~
0.1 - 3.0 i~ alkali or acidO ~he resulting active eluate
may be lyophilized to afford a crude powder of substance
Kl~-70380
Examples of the weak acidic cation exchange
resin used to recover th.e substance KA-7038 are Amberlite
I~C-50, IRC-84 and CG-~0 (Rohm & Haas Co.); and Diaion
WK-10 end ~K-20 (Mitsubishi Chemical Co.~ Ltd~).
Examples of alkalies that can be used for the elution
are ammonium hydroxide solutlon, and an aqueous solution
of sodium hydroxide. ~xamples of the acids are formic
acid, hydrochloric acid and sulfuric acid~ Another
example of the recovering method comprises adjusting
the pH of the culture broth filtrate to 7 to 9, con-
tacting the filtrate with active carbon to cause thesubstance ~A-7038 to adsorb to the ~ctive carbon, and
eluting the substance with acidic waterO
~ he substance KA-7038 that can be isolated
by the methods described above can be separated in-to
KA-7038 I, II, III, IV, V, VI and VII by dissolving
it in water charging it on a column of an adsorbent
such as a weak acidic ion exchange resin of the type
described above or a weak acidic ion exchanger such as
CM_sephadex or C~-cellulose to cause the substance to
be adsorbed to the adsorbent, and then eluting it with
an alkaline aqueous solu-tion such as dilute ammonium
hydroxide, or an aqueous solution of ammonium carbonate
or ammonium formate by a gradient method or a stepwise
frQ~ /~1R rk

285
method~ According to this separating procedure, sub-
, ~ stance ~A-70~8 IV, substance ~A-7038 VII, substance
KA_7038 I, substance KA_7038 II, substance XA-7038 VI,
substance KA-7038 III and substance KA-7038 V as free
bases are separated successively.
rrhe resulting substances KA-7038 I, II, III,
IV, V, VI and VII separated can be in powder form by
concentrating the eluate and lyophilizing the condensate.
rrhey can be purified by column chromatography on, for
10 example, cellulose, strong basic anion exchange resin.
~or example, dissolving the powder in water, causing
them to be adsorbed to a column of a strong basic anion
exchange resin such as Dowex11x2 (Dow Chemical), eluting
them with deionized water, collecting active fractions,
15 and lyophilizing the collected fractions. rrhese sub-
stance KA-7038 obtained as free base can be converted
to their acid addition salts by treatment with pharmaceu-
tically acceptable inorganic or organic acids. h~amples
A f such acids are inorganic acids such as sulfuric acid~
i 20 hydrochloric acid, hydr~iodic acid, phosphoric acid,
carbonic acid, nitric acid etc~, and organic acids such
as acetic acid, fumaric acid, maleic acid, citric acid,
mandelic acid and succinic acid.
rhe substance KA-7038 III has the structural
25 formula of the substance I~A-7038 I in which the glycyl
group -COCH2~2 is split off. r~herefore, the substance
KA-7038 III can also be obtained by treating the sub-
stance K~-7038 I with alkalies or acids to decompose

~5~285
the substance KA-7038 I and convert it to substance KA-7038 III. This conversion
can be effected by treating the substance KA-7038 I with a 0.1 - 4 N aqueous
solution of an alkaline reagent such as sodium hydroxide or barium hydroxide or
with a 0.1 - 1 N aqueous solution of an acidic reagent such as hydrochloric acid
or sulfuric acid.
In the case of using the alkaline reagent, a strong basic anion ex-
change resin [e.g., Amberlite* IRA 400 (OH form) or Dowex* lx2 (OH form)] may
be added, and the reaction can be performed in the suspended state Likewise,
when the acidic reagent is used, a strong acidic cation exchange resin such as
Amberlite* lR 120 (H form) or Dowex* SOx8 (H fo~m) may be added, and the
reaction can be performed in the suspended state. The reaction can be performed
usually at about 30 to 100 C for about 0.5 to 3 hours.
In the practice of the process of this invention, the compound of
formula II or its protected product at the amino or the methylamino groups at
the 1-, 2'- and 6'-positions is reacted with a strong acid in the presence or
absence of a solvent. This reaction induces the cleavage of the methyl ether
at the 5-position and the splitting off of R3 bonded to the methylamino group
at the 4-position when it is an acyl group. Thus, a compound of formula I in
which a hydroxyl group is present at the 5-position and R3 is a hydrogen atom
can be obtained.
Examples of the strong acid are strong mineral acids such as hydro-
bromic acid, hydrochloric acid, hydriodic acid, hydrofluoric acid, sulfuric acid
and phosphoric acid; strongly acidic organic acids such as p-toluenesulfonic
acid and trifluoromethanesulfonic acid; and Lewis acids such as boron tri-
chloride and boron trifluoride. When a Lewis acid is used, the reaction is
preferably carried out in an anhydrous condition. In other cases, the reaction
is preferably carried out in aqueous solution. For example, dichloromethane
*Trade Mark
14 ~

can be used as an anhydrous solvent.
The reaction can be carried out, for example, at room temperature to
about 200 C. Usually, the reac-tion ends in about 1 hour to about 30 days. The
product can be separated and purified by an ordinary colurm chromatographic
method, for example by using a cation exchange resin. Acylation of the methyl-
amino group at the 4-position of the resulting compound of formula I in which
R3 is a hydrogen atom affords a compound of formula I in which R3 is an acyl
group as defined above.
Ir. performing the acylation, the amino or methylamino groups at the
1-, 2'- and 6'-positions of the compound of formula I in which R3 is a hydrogen
atom and -OH is present at the 5-position are protected, and then an optionally
substituted amino acid (preferably protected) or its reactive derivative for
forming the desirable acyl group is caused to act on the protected compound to
acylate the methylamino group at the 4-position. Subsequent deprotection can
afford the compound of formula I as a free base. If desired, the product is
treated with an acid to convert it to an acid addition product.
Protective groups for an amino or methylamino group may be those used
ordinarily in peptide synthesis. For example, when an active ester such as a
substituted phenyl ester (e.g., monobenzyl carbonate), N-oxysuccinimide ester
or N-oxyphthalimide es-ter is used, only the amino or methylamino groups at the
1-, 2'- and 6'-positions are protected by a benzyloxycarbonyl group. The
presence of a metal compound such as nickel acetate, cobaltous acetate and
copper acetateduring the protecting reaction is preferred. Substituted benzyl-
oxycarbonyl groups and tertiary butoxy carbonyl group may also be used as pro-
tect;ve groups. When the methylamino group

l.l~ii~Z85
at the 4-position is simultaneously protected, it can be
liberated by reacting the product with an alkali to form
a cyclic carbamate with the hyAroxyl group adjacent to
the methyl~mino grou~ at the ~-position, and then hydrolyz-
ing ito .
~he aforesaid introduction of a protective
group into the amino or methylamino groups can be effec-
ted, for example, by causing the active ester to act on
the compound of formula (I) wherein R3 is hydrogen at a
temperature of about 0 to about 100C preferably in the
presence of a metal compound, the amount of the active
ester being about 3 to about 10 moles per mole of the
compo~nd of formula (I). ~he reaction can be terminated
usually in about 0~5 to about 20 hoursO
According to the method of this invention, an
acyl group is introduced, if desired, into the methyl-
amino group at the 4-position of the compound of formula
(I) in which R3 is hydrogen and the amino or methyl-
amino groups at the 1-, 2'- and 6'-positions is protected.
The ~cylation can be performed by using a conventional
peptide synthesizing technique. hcylation is carried
out using an amino protected amino acid or another sub-
stituted carboxylic acid or a reactive derivative thereofO
Examples of the reactive derivative are acid halides,
active esters such as a phenyl ester, cyanomethyl ester,
N_oxysuccinimide ester or N-oxyphthalimide ester, acid
azides, acid anhydrides, mixed acid anhydrides, and
other compounds which are used in the synthesis of

Z8S
peptides. Protective groups for the amino group of the amino acid may be the
same as those exemplified hereinabove for the amino or methylamino groups of
the compound of formula I in which R3 is hydrogen. Preferably~ quite the same
protective groups should be used.
The acylation reaction can be performed, for example, at a temperature
of about 0 to about 100 C in a solvent such as methanol, dioxane, acetonitrile
and dichloromethane by using about 1 to about 10 moles of an acylating agent
per mole of the compound to be acylated. Usually, the reaction can be termin-
ated in about 0.5 to about 20 hours.
Preferably, the protective groups for the amino groups are spli-t off
from the protected compound of formula I preferably by a catalytic reducing
method. Suitable catalysts for this purpose include palladium, platinum, Raney
nickel, rhodium, ruthenium, and nickel.
Splitting off of the protective groups by catalytic reduction can be
performed, for example, by reacting the protected compound in a solvent such as
acetic acid in the presence of a catalyst at a temperature of about 0 to about
80 C for about 1 to about 50 hours. The hydrogen pressure at this time may be
normal or atmospheric pressure or an elevated pressure.
In the present invention, the compound of formula I that can be ob-
tained from the compound of formula II in the above manner can be isolated and
purified in a customary manner. Column chromatography is preferred. Preferred
adsorbents for this purpose are cation exchange resins such as CM-Sephadex*,
Amberlite* IRC-50, Amberlite* IRC-84, Amberlite* CG-50, and carboxymethyl cellu-
lose. Development can be performed by a gradient method or a stepwise method
using an alkaline aqueous solution such as an aqueous solution of ammonia or an
aqueous solution of ammonium formate as a developing solvent. The active frac-
tions are collected from the eluates, and lyophilized to obtain the compound of
formula I in pure form.
Depending upon the purifying operation, the desired product (I) may
T~ A ~
- 17 -
.

also be obtained in the form of an acid addition salt. The compound (I) as a
free base can be converted to an acid addition salt thereof, preferably a
pharmaceutically acceptable acid addition salt thereof, in a customary manner.
Acids for this purpose include, for example, inorganic acids such as sulfuric
acid, hydrochloric acid, hydrobromic acid, hydriodic acid, phosphoric acid,
carbonic acid and nitric acid, and organic acids such as acetic acid, fumaric
acid, malic acid, citric acid, mandelic acid and succinic acid.
According to the process of this invention, the desired compounds of
formula I having antibacterial activity can be obtained easily and in good
yields from KA-6606 and KA-7038 substances having a structure similar to the
fortimicins.
The compounds of formula I are compounds not described heretofore in
the literature. The compounds of formula I exhibit superior antibiotic
activity, and are useful in the field of medicines for man and animals, and also
as intermediates for the synthesis of derivatives.
Thus, the present invention can provide an antibiotic composition
comprising the novel compounds of formula I.
Specifically, according to this invention, there is provided an anti-
biotic composition composed of
(i) an antibiotically effective amount of a compound having the
following formula
Tl
6' CH-NH-R2 ~NH2
~ ~
>~OH
NH 2 N- CH 3
. --.
s' ~ - 18 -

~5~ 5
wherein Rl and R2 are identical or diEferent, and each represents a hydrogen
atom or a methyl group, and R3 represents a hydrogen atom or an optionally sub-
stituted aminoacyl group having 2 to 4 carbon atoms in the acyl moiety, the
substituent being a formyl or carbamoyl group, provided that when all of Rl, R2
and R3 are hydrogen atom, the methylamino group at the 4-position is not
oriented trans to the hydroxyl groups at the 3- and 5-positions; or a pharmaceu-
tically acceptable acid addition salt thereof; and
(ii) a pharmaceutically acceptable diluent or carrier.
The amount of the compound (I) is, for example, about 0.01 to about
99.5~ by weight, based on the weight of the composition.
The antibiotic composition of this invention may be in any dosaye
forms usually employed, but injecting preparations and capsules are especially
preferred.
Preferably, like known water-soluble basic antibiotics, an injectable
is prepared by filling a lyophilized powder of the antibiotic into a vial, pre-
ferably together with a s~abili~er, and in use, the contents of the vial are
dissolved in a dissolving liquid for administration.
The diluent or carrier includes, for example, liquid diluents such as
distilled water for injection and physiological isotonic solution, and solid
carriers
-- 19 --

~5~Z85
such as lactose, starch7 white sugar, glucose, crystalline
~ ~_
cellulose, calcium carbonate, kaolin, D-mannitol,
magnesium metasilicate aluminate, calcium sulfate, ca-
lcium phosphate and bentonite. r~ddition of stabilizers
such as acidic sodium bisulfite is also preferredO
The dosage of the antibiotic substance of this
invention can be suitably selected, and is, for example,
about 0.01 to about 100 mg/kg/day~
Thus, according to this invention, there can
be provided antibiotic compositions for animals other
than human, such as poultry, domesticated animals and
cultivated fish, and an-tibiotic compositions for human.
These compositions are useful as antibacterial agents
having a broad antibacterial spectrumO
Table 1 below summarizes the antibacterial
spectra of several examples of the compound of formula
(I)-l and starting materials therefor~

~2~5
~1
Table
¦ De-O- 4-~- I De-O- ¦ De-O-
methyl glycyl m~_hNyl l methyl
! glycyl l l
KA- I KA_ KA- KA- I KA- I KA_
6606I ¦6606I 6606VI 6606V1 ¦ 7038I7038I
I _ _ _ I
Staphylococcus
aureus 209P I 0.2 0.2 0.39 0039 0.390.39
Baeillus subtilis
AlrCC 6633 0.2<0.1 0.20 0.20 0.20<0.1
Bacillus cereus 1056 10078 0078 9.78 1.560039
Baeillus anthraeis 0.2 1 <0~1 0.20 0.20 0.20 <Ool
Streptococcus l
faecalis 25 25 25 25 5 100
Escherichia coli
NIHJ 1.561.56 1.56 1.56 3.133.13
Eseherichia coli
1410 lr 561.56 3.13 3.13 1.561.56
Eseherichia eoli
M~1410R-81 3.131.56 6.25 3.13 60253.13
(resistant to
kanamyei:~,
streptomyein and
lividomycin)
Escherichia coli
ML1410R-82 3.133013 6025 6.25 12.56.25
(resistant to
kanamycin,
streptomycin and
butirosin)
Escherichia coli .
M11410R--101 lr5611.56 3.13 ¦ 3.13 6.253~13
(resistant to
gentamiein,
tobramycin and
kanamycin)
Proteus vulgaris
OX-19 1 0.78l0~78 1056 ! 1.56 3-13 l3-13
! .- to be continued-

~ ~5~ 35
~able - 1 - (continued)
Klebsiella I I l
pneumoniae PCI 602 ¦ 0 ~ 78 0 ~ 78 0 ~ 78 0 ~ 78 1.56 0~ 78
Psudomonas I
A ae~uginosa Shibata ¦ 3~13 0~78 6025 1~56 6~25 1~56
Pseudomonas I
aeruginosa A3 3.13 0 ~ 78 6 ~ 25 3.13 12 ~ 5 3.13
Pseudomonas
aerugi.nosa No ~ 12 0 ~ 39 1 0 ~ 39 0 ~ 78 0 O 78 1 ~ 56 0 ~ 78
Pseudomonas I
aeruginosa ~I-13 3~13 ! 0~78 3~13 3~13 6025 1~56
Pseudomonas
aeruginosa E-ll 6~25 lo 56 6~25 6~25 12~ 5 3~13
(resistant to
kanamycin)
Pseudomonas
aeruginosa No. 157 6~25 1~ 56 3~13 lo 56 6~25 lo 56
Pseudomonas
aeruginosa l~o. 315 6~25 3~13 12~5 6~25 25 6~25
(resistant to I
gentamicin
tobramycin and
amikacin)
Proteus
inconstans 1. 56 1.56 1.56 1.56 6 ~ 25 6~ 25
Serratia ~ } 56 0~78 1~56 1.56 ¦ 0~78

~Q
~ he following examples show the production of
the compounds of this invention and the production of
known de-0-methyl-fortimicin by the process of this
invention~
Example 1
De-0-methyl-KA-6606 II:-
KA-6606 II as a free base (lol g) was dissolved
in 100 ml of 4~,/i hydrobromic acid, and the solution was
heated in a sealed tube at 90C for 4 hours. The reac-
tion mixture was concentrated -to dr~ness under reduced
pressure. ~he residue was dissolved in water, and neu-
tralized with conc~ aqueous am~onia. ~he solution was
charged on a column packed with 400 ml of CMl-Sephadex
C-25 (NH4 form), and eluted with aqueous ammonia of a
concentration varying gradually from 0O05 N to 0.5 No
Fractions containing de-0-methyl-KA-6606 II were col-
lected, and treated in a customary manner to afford 620
mg of de-0-methyl-~A-6606 II as a colorless compound
having the following formulaO
CIH3
CH~H2
t ~ C~3
~\ /~
I H
'~H2
.... ~ ~ .
~.

285
d ;J,
Specific ro-tation: ~a~25 + 140 (~2, H20)
NMR: ~ D20 ppm
1053 (3H, d, J=603 Hz, C-C~)
2088 (3H, s, N-C~)
5.46 (lH, d, J=304 Hz, anomeric H)
~lemental analysis: fbr Cl~H~oN404~H20
Calculated (,b): C 49.98 H 9059 N 16.65
Found (~) C 49.69 H 9.73 N 16.~8
Example 2
(a) Tetrakis-N-benzyloxycarbonyl-de-o-methyl-K~-66o6 I:-
De-0-methyl-KA-5606 II as a free base (60 mg)
was dissolved in 5 ml of methanol, and at -10C, 75 mg
of N-benzyloxycarbonyloxy succinimide was added. The
mixture was stirredO At the end of 1 hour, and 2 hours
respectively, 30 mg and 20 mg of the aforesaid active
ester were added. ~he mixture was further stirred at
the same temperature for 2 hours. ~he reaction mixture
was concentrated under reduced pressure. ~he residue was
dissolved in 10 ml of chloroform, washed with water, and
dried, followed by distilling off the solvent~
~ he residue was dissolved in 305 ml of dioxane,-
and 0.2 ml of triethylamine and 100 mg of N-hydroxysucci-
nimidyl-N~benzyloxycarbonylglycine were addedO ~he mix-
ture was heated at 60C overnight. The reaction mixture
was concentrated to drynessO ~he residue was dissolved
in 10 ml of chloroform, washed with water and dried,
followed by distilling off the solvent. ~he residue was
chromatographed on a silica gel column using chloroform-

~5~Z~3S
methanol (50:1) as an eluent, and finished in a customary manner to afford 62mg of tetrakis-N-benzyloxycarbonyl-de-O-methyl-KA-6606 I as a colourless solid.
Specific rotation: [~]D + 37 (c 2, CHC13)
NMR: ~ CDC13, ppm
1.01 (3H, d, J=6.5 Hz, C-CH3)
2.91 (3H, s, N-CH3)
IR: v 3 cm 1 1640 (amide I)
max
Elemental analysis: for C48H57N5O13
Calculated (~): C 63.22 H 6.30 N 7.68
Found (~): C 63.28 H 6.35 N 7.55
(b) De-O-methyl-KA-6606 I:
The tetrakis-N-benzloxycarbonyl-de-O-methyl-KA-6606 I (60 mg) obtained
in (a) above was dissolved in 1.2 ml of acetic acid, and hydrogenolyzed in the
presence of 30 mg of palladium black at room temperature and atmospheric
pressure. The catalyst was removed by filtration, and the filtrate was diluted
with 100 ml of water and neutralized in conc. aqueous ammonia. The solution
was charged on a column packed with 10 ml of CM-Sephadex* C-25 (NH4 form), and
eluted by a gradient method using aqueous ammonia of a concentration varying
gradually from 0.05 N to 0.5 N. Fractions containing the desired compound
were collected, and lyophilized to afford 21 mg of de-o-methyl-KA-66o6 I as a
colourless solid having a melting point of 172 to 175 C (decomp.) and the
following formula.
CH3
CHNH2
~COCH211H2
NH2 OH
*Trade Mark
- 25 -
~ .

~5~Z1 3S
Elemental analysis: for C16H33N505.H2C03.H20
Calculated (%): C 44.83 H 8.19 N 15.38
Found (%): C 44.47 H 8.38 N 15.05
The hydrochloride of this product obtained by a conventional method
has the following properties.
Specific rotation: [~]D + 110 (c 2, H20)
NMR: ~ D20 ppm
1.83 (3H, d, J=6.6 Hz, C-CH3)
3.63 (3H, s, N-CH3)
6.03 (lH, d, J=3.6 Hz, anomeric H).
Example 3
De-0-methyl-KA-6606 II:
KA-6606 II as a free base (100 mg) was suspended in 5 ml of dichloro-
methane, and 5 g of boron trichloride was added at -80 C. The mixture was
allowed to stand at the same temperature for 1 hour. Then, at room temperature,
it was allowed to stand overnight. The reaction mixture was concentrated to
dryness, and methanol was added to the residue. The mixture was again concen-
trated to dryness. This operation was repeated three times.
The resulting residue wa~ dissolved in 10 ml of water, and the solu-
tion was charged on a column packed
- 26
, .
,.~'' ! .

- ~5~Z85
~1
with 4-0 ml of CM-SephadexlC-25 (~I4 form), and eluted
by a concentration gradient method using aqueous ammonia
of a concentration gradually varying from 0.05 N to 0.5 N.
Fractions containing de-0-methyl-KA-6606 II were collec-
1~ ~q
ted, and finished in a customary manner to obtain 15fm~
A of a colorless substanceO ~he properties of this product
were identical with those of the de-0-methyl-KA-6606 II
obtained in Example lo
Example ~
De-0-methyl-K!'-6606 VI:-
KA-6606 VI as a free base (350 mg) was dis-
solved in 3.5 ml of 56~ hydriodic acid, and heated at
60C in a sealed tube for 4 hours. ~he reaction mix-
ture was concentrated to dryness under reduced pressure.
~he residue was dissolved in water, and neutralized with
conc. aqueous ammoniaO ~he solution was charged on a
column packed with 30 ml of CM-Sephadex1C-25 (NH4 form),
and eluted with a~ueous ammonia of a concentration
varying gradually from 0025 N to 0O35 N. Fractions con-
taining the desired product were collected, and concen-
trated to dryness to obtain 265 mg of de-0-methyl-
KA-6606 VI having the following formulaO
ICH3
,CHNH2 NH2
CH3
O /~
~H OH

Z85
-- 3R --
~lemental analysis: for C14H30N404 ~H20
Calculated (y~): C 49O98 E 9.59 N 16.65
Found (/v): C 49065 H 9~L~ N 16.61
Specific rotation: ~a~23 ~ 87 ~ 1, H20)
~~~ 5 I~IR: S D20 ppm
lo54 (3H, d, J--6.5 Hz, C-CH~)
2.85 (3H, s, ~-CH3)
~ 6 (lH, d, J=3O3 Hz, anomeric H)
Example ~
(a) 1,2',6'-tris-N-benzyloxycarbonyl-4-N-benzyloxy-
carbonylglycyl-de-0-methyl-~-6606 VI:_
De-0-methyl-KA-6606 VI (163 m~) was dissolved
in 5 ml of methanol, and 273 mg of nickel acetate w~s
added. The mixture was stirred at room temperature for
3 minutes, and then 454 mg of N-benzyloxycarbonyloxy-
succinimide was added. ~he mixture was stirred at the
same temperature for 2 hours. Conc. aqueous ammonia
(2.5 ml) was added to the reaction mixture, and the
mixture was stirred for 2 hours. The reaction mixture
was concentrated under reduced pressure, and the residue
was dissolved in 20 ml of chloroform and 3N~ aqueous
ammonia. !rhe solution was shaken. 'rhe chloroform layer
was separated, washed twice with 3N~ aqueous ammonia and
twice with water, and dried, followed by distilling off
the solvent.
~ he residue was dissolved in 9 ml of dioxane,
and 330 mg of 2,L~-dinitrophenyl ester of N_benzyloxy_
carbonylglycine and 0.3 ml of triethylamine were added,

3~S~85
and the mix~ure was heated at 60C for 1 hour~ ~o the
reaction mixture was added 1 ml of concO aqueous ammonia,
and the mixture was allowed to stand for 1 hourO ~he
solvent was then distilled off. '~he residue was dis-
solved in 20 ml of chloroform, and washed three timeswith 0.5 N aqueous so~lium hydroxide solu-tion and twice
with water, and dried, followed by distilling off the
solvent. The residue was chroma-tog~aphed on a silica
gel column using chloroform/methanol (50:1) as an eluent.
Fractions containing the desirea product,were collected,
and concentrated to afford 288 mg of -~2' ~-tris-N-
.benzyloxycarbonyl-4-N-benzyloxycarbonylglycycl-de-0-
methyl-KA-6606 VI as a coloress ~qolidO
Elemental analysis: for Cb,~
Calculated (/0): C 63.22 H 6.30 N 7.68
Found (/): C 63.43 H 6021 N 7O44
Specific rotation: ~a~D3 + 32 (~ 1, CHC13)
NMR: ~ CDC13 ppm
2092 ( 3H, s, N-C~)
ln21 (3H, d, J=6 Hz, CH-CH~)
~b) De-0-methyl-4-N-glycyl-KA-6606 VI:-
~he 1,2',6'-tris-N-benzyloxycarbonyl-4-N-
benzyloxycarbonylglycyl-de-0-methyl-KA-6606 VI (288 mg)
obtained in (a) above was dissolved in 4 ml of acetic
acid, and 50 mg of palladium black was added. The above
compound ~as then catalytic~lly reduced at room tempera-
ture. ~he reaction mixture was filtered. ~he filtrate
was diluted with 400 ml of water, and neutralized with

3 ~5~Z85
E aqueous ammonian ~he solution was charged on a column of
¦~ CM-Sephadex1C-25 (NH4 form), and eluted by a concentra-
tion ~radient method using aqueous ammonia of a concen-
tration gradually varying from 0.05 N to 0.35 No Frac-
tions containing the desired product were collected, and
lyophilized to afford 105 mg of de-0-methyl-4-N-glycyl-
KA-6606 VI as a colorless solid having the following
formula~
ICH3
CH2NH2 NH2
CO CH2NH2
~H2 ~[
lO ~lemental analysis: for C16H3 ~505.H20
Calculated (,S): C 48084 H 8.97 N 17080
Found (/~): C 48055 H 8.83 N 17.48
Specific rotation: C~)~3 ~ 115 (~ 1, H20)
A l~R: ~ D20 ppm
1.52 (3H, d, J=605 Hz, C-C~)
3062 (3H, s, N-C ~)
5.40 (lH, d, J=3 Hz, anomeric H)
~xamPle ~
De-0-methyl-KA-6606 VI:-
KA-6606 VI (100 mg) was dissolved in 5 ml of
48% ~ydrobromic acid, and the solution was allowed to
stand at 37C for lO daysO The reaction mixture was
concentrated to dryness at below 37C. The residue was

~15~'~85
31
dissolved in 50 ml of water, and neutralized with aqueous
a~monia. The solution was charged on a column of CM-
Sephadex~C-25 (1~4 ~orm), and eluted by a concentration
gradient method using aqueous ammonia of a concentration
varying gradually ~rom 0~05 i`~ to 0O5 ~ to afford 19 mg of
de-0-methyl-~A-6606 VI. The properties of the product
were identical with those of the de-0-methyl-KA-6606 VI
obtained in Example ~.
Example ~
1,2',6'-tris-l~Lbenzyloxycarbonyl-4-N-benzyloxy-
carbonylglycyl-de-0-me-thyl-~A-6606 VI:-
De-0-methyl-~A-6606 VI (19 mg) was dissolved
in 0.8 ml of methanol, and 90 mg of benzyl p-nitrophenyl
carbonate was addedO ~he mixture was stirred overnight
at room temperature. To the reaction mixture was added
0.1 ml of a 30% ethanol solution of methylamine, and the
mixture was further stirred for 1 hourO Then, the reac-
tion mixture was concentrated to dryness. The residue
was dissolved in chloroform, washed with weter, and
dried. The product was dissolved in 1 ml of dioxane,
and 0.05 ml of triethylamine and 35 mg of i~-hydroxysuc-
cinimidiyl-N-benzyloxycarbonyl glycine were added, and
the mixture was heated at 80C for 5 hours. The reac-
tion mixture was concentrated to dryness~ The residue
was dissolved in chloroform, and the insoluble matter
was separated by filtration. The chloroform layer was
washed with water, and dried, followed by distilling
off the solvent~ The residue was separated and purified

2~3S
by silica gel preparative chromatography (chloroform/methanol in a ratio of
15:1) to afford 23 mg of 1,2',6'-tris-N-benzyloxycarbonyl-4-N-benzyloxycarbonyl-
glycyl-de-O-methyl-KA-6606 VI as a colourless solid. The properties of the
product were identical with those of the compound obtained in Example 5, (a).
Example 8
De-O-methyl-KA-7038 III:
KA-7038 III as a free base (302 mg) was reacted in the same way as in
Example 4. On purification, 220 mg of de-O-methyl-KA-7038 III was obtained as a
colourless powder having the following formula.
CH2NHCH3 NH2 CH
~ O ~ 3
~ ~ H
OH
NH2
Elemental analysis: for C14H30N4O4.H2O
Calculated (%): C 49.98 H 9.59 N 16.65
Found (%): C 49.71 H 9.73 N 16.33
Specific rotation: [~]D + 40 (c 0.5, H2O)
2.80 (3H, s, N-CH3)
2.84 (3H, s, N-CH3)
5.53 (lH, d, J=3.3 Hz, anomeric H).
Example 9
(a) Tetrakis-N benzyloxycarbonyl-de-O-methyl-KA-7038 I:
De-O-methyl-KA-7038 III (190 mg) was reacted in the same way as in
Example 5, (a). On purification, 350 mg of 1,2'6'-tris-N-benzyloxycarbonyl-4-
N-benzyloxycarbonylglycyl-de-O-methyl-KA-7038 III, i.e. tetrakis-N-benzyloxy-
32 ~
., ~

-
~5~2B5
carbonyl-de-O-methyl-KA-7038 I, was obtained as a colourless solid.
Elemental analysis: for C48H57N5C13
Calculated (%): C 63.22 H 6.30 N 7.68
Found ;%): C 63.01 H 6.49 N 7.42
Specific rotation: []D + 55 (c 1, CHC13)
CDC13
2.92 (6H, s, 2xN-CH3)
(b) De-O-methyl-KA-7038 I:
Tetrakis-N-benzyloxycarbonyl-de-O-methyl-KA-7038 I (320 mg) was
treated in the same way as in Example 5, (b) to afford 112 mg of de-O-methyl-
KA-7038 1 as a colourless solid having the following formula.
CH2NHCH3 NH2
COCH2NH2
NH2
Elemental analysis: for C16H33N5O5-H2O
Calculated (%): C 48.84 H 8.97 N 17.80
Found (~): C 48.54 H 8.69 N 17.98
Specific rotation: [~D + 126 (C 1, H2O)
D20
2.83 (3H, s, 6'-N-CH3)
3.63 (3H, s, 4-N-CH3)
5.42 (lH, d, J=3 HZ, anomeric H).
Example 10
1,2',6'-tris-N-benzyloxycarbonyl-4-N-[(S)-4-benzyloxycarbonylamino-2-
- 33 -

~5~ 8S
hydroxybutyryl]-5-de-0-methyl-KA-6606 II:
138 mg of 1,2',6'-tris-N-benzyloxycarbonyl-5-de-methyl-KA-6606 II (1)
was dissolved in 4 ml of dioxane, and 130 mg of N-hydroxysuccinimide ester of
(S)-4-N-benzyloxycarbonylamino-2-hydroxybutyric acid and 0.1 ml of triethylamine
were added. The mixture was heated at 55 C for 3 hours. The reaction mixture
was concentrated to dryness. The residue was dissolved in 20 ml of chloroform,
washed with water, and dried, and then the solvent was distilled off. The
residue was eluted with chloroform-methanol (30:1) by silica gel column
chromatography, and finished in a customary manner to afford 160 mg of the
desired product as a colourless solid.
NMR: ~ CDCl, ppm
3.04 (3H, s, N-CH3)
1.03 (3H, d, J=7.0 Hz, C-CH3)
IR: v 1625 cm (amide I)
Elemental analysis: for C50H61N5014
Calculated (%): C 62.81 H 6.43 N 7.32
Found (%): C 62.55 H 6.19 N 7.48.